1. Field of Invention
This invention relates to repair of cracked building and paving material surfaces, specifically to surfaces for which functional or aesthetic restoration of the repaired surface is desired.
2. Description of the Prior Art
Cracked building and paving materials are commonly repaired for functional and/or aesthetic reasons, as well as to retard further deterioration.
Historically, cracked surfaces are cleaned and sealed using a variety of grout mixtures and other sealents or fillers in an attempt to prevent further deterioration, to prevent or reduce movement of the cracked area, and to restore continuity of the surface. However, such repairs are generally acknowledged to be temporary and require continuing maintenance and repair due to continuing movement of the crack with changing environmental conditions such as temperature and moisture fluctuations. This sequence of deterioration and repair commonly continues until the surface is no longer functional for its intended purpose and either an entirely new surface is applied or the old material removed and replaced.
Although a number of grout mixtures and processes have evolved, there has yet to be a system of crack repair which will withstand continuing movement of the crack while maintaining a smooth uncracked and functional surface. Existing techniques and methods simply do not produce a long lasting repair. Current repair methods do not prevent re-cracking of the surface because there is no provision to alleviate stresses induced as a result of continuing crack movement, or to strengthen materials above the crack. Repaired surfaces re-crack and become unsightly or nonfunctional because of tensile or compressional forces related to crack movement, and they do not produce surfaces suitable for many purposes, such as tennis court surfaces, where a smooth playing surface of uniform characteristic is mandatory.
Several alternatives to crack repair are also in common use. These include removal or partial removal of the original building or paving material and replacement with new material. This is an expensive and time consuming process. Another option is to overlay the existing surface with additional building or paving material, which is also a relatively expensive process and may not be practical in many situations where the elevation and orientation of the original surface must be maintained. It is also common for the overlay material to crack at the surface in the same locations as the original cracked building or paving material.
Although these various methods of crack repair are in extensive use, it is common knowledge that such repairs are either temporary, costly, or both. With the exception of complete removal and replacement of the building or paving material, existing crack repair products and methods suffer from a number of disadvantages:
(a) Grout mixtures placed within the crack are subject to the same deteriorating elements as the original material. Other than coating the surface with moisture resistant paint, there is no method to reduce this deterioration.
(b) The materials and methods currently used do not have any greater inherent tensile or compressive strength than the original building or paving material and thus are subject to recracking under the same stresses which created the original crack.
(c) If special coatings are required on the material surface, such as on recreational playing surfaces, the crack filling material may not adhere to the newly applied surface material, thus producing additional stresses on the surface and/or different surface characteristics, such as the way a tennis ball bounces upon impacting the repaired area.
(d) There is no mechanism to reduce surface and near surface stresses which created the original crack.